Odd problem with game after using Magpie.

[dannyboy1121]

EDIT: - It turns out the problem was not Magpie related. Separate Intel ARC retro scaling option had been changed on the PC.
Feel free to delete.

---

I run a game in 1080p on a 1440p monitor and the game previously stretched the window to full screen.
Recently, I've used Magpie to upscale using FSR (ver 0.10.3), running the game at 1080p in windowed mode, and Magpie upscaling and running fullscreen.

After doing this, if I try to run the game at 1080p fullscreen without Magpie, the game screen no longer stretches, and presents as a 1080p image with a large black border.

I don't rightly understand how Magpie intercepts the game screen, but could some kind of abnormal terminal event have left an asset that's interfering, even when Magpie isn't active? If so, how could I clear that down?

Any help would be appreciated.